Optical member and optical display device

Abstract

To provide an optical member having a small amount of change in light transmissivity at a 380 nm of wavelengths even when exposed to ultraviolet light for a long period of time under a temperature change repeated between ordinary temperature and high temperature.SOLUTION: The optical member contains an adhesive layer and a substrate film laminated on one surface of the adhesive layer, in which an adhesive layer comprises a cured product of a composition comprising a UV absorber and a (meth)acrylic copolymer. The optical member has a change in light transmittance ▵T of 0% in Equation 1, a change ▵b* in the b* value of the hue in Equation 2 being less than 0.4. [Equation 1] ▵T=|T2 - T1| [Equation 2] ▵b*=|(b*2) - (b*1)|.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an optical member and an optical display device including the same. [Background technology]

[0002] Light-emitting display devices, including organic light-emitting display devices, do not necessarily have to include a polarizing plate. However, incident external light may be totally reflected by the panel in the light-emitting display device, resulting in a decrease in screen quality. For this reason, light-emitting display devices generally include a polarizing plate on the upper surface of the panel. The polarizing plate is composed of a polarizer and a retardation film. The polarizing plate contains a UV absorber, which also serves to prevent damage to the light-emitting element by external light.

[0003] In recent years, optical display devices have tended to become thinner, and attention has been focused on the development of optical display devices that do not include polarizing plates (POL-LESS optical display devices). However, in such display devices that do not include polarizing plates, the light-emitting elements are directly exposed to external light, making the light-emitting elements more susceptible to damage.

[0004] The background art of the present invention is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2015-010192 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an optical member that exhibits a small change in light transmittance at a wavelength of 380 nm even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature.

[0007] Furthermore, the present invention is also capable of maintaining the color b even after long-term exposure to ultraviolet light under repeated temperature changes between room temperature and high temperature. * One of the objects is to provide an optical member in which the amount of change in value is small.

[0008] Another object of the present invention is to provide an optical member that has a high peel strength from a panel for an optical display device and is excellent in durability. [Means for solving the problem]

[0009] An embodiment of the present invention is an optical member.

[0010] The optical member includes an adhesive layer and a substrate film laminated on one surface of the adhesive layer, and the adhesive layer includes a cured product of a composition including a UV absorber and a (meth)acrylic copolymer. The optical member has a change in light transmittance ΔT of 0% in the following formula (1) and a change in hue b of 0% in the following formula (2). * Amount of change in value △b * is less than 0.4.

[0011] [Formula 1] △T=|T2-T1|

[0012] In Equation 1, T1 is the light transmittance (unit: %) of the optical component at a wavelength of 380 nm, T2 is measured by holding the optical component at 25°C for 4 hours, then at 63°C for 8 hours, while exposing the optical component to light at a wavelength of 340 nm and an intensity of 0.35 W / m 2 This is the light transmittance (unit: %) of the optical member at a wavelength of 380 nm after a total of 21 cycles of light irradiation, which is defined as one cycle.

[0013] [Formula 2] △b * =|(b * 2)-(b * 1)|

[0014] In Equation 2, (b * 1) is the hue of the optical component b *is the value, (b * 2) The optical component was kept at 25°C for 4 hours, and then at 63°C for 8 hours, during which time the optical component was exposed to light with a wavelength of 340 nm and an intensity of 0.35 W / m 2 The hue of the optical component after a total of 21 cycles of light irradiation is b * value.

[0015] Another embodiment of the present invention is an optical display device.

[0016] An optical display device includes the optical member. [Effects of the Invention]

[0017] The present invention can provide an optical member that exhibits little change in light transmittance at a wavelength of 380 nm even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature.

[0018] The present invention is characterized by the fact that the color b of the dye remains unchanged even after long-term exposure to ultraviolet light under repeated temperature changes between normal and high temperatures. * It is possible to provide an optical member with a small amount of change in value.

[0019] The present invention can provide an optical member that has a high peel strength from a panel for an optical display device and is excellent in durability. DETAILED DESCRIPTION OF THE INVENTION

[0020]

[0033] The present invention will now be described in detail with reference to examples so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described below.

[0021] The terms used below are merely used to describe exemplary embodiments and are not intended to limit the present invention. Unless otherwise specified in the context, singular expressions include plural expressions.

[0022] As used herein, the term "glass transition temperature of a homopolymer" refers to the glass transition temperature (Tg) of a homopolymer of a target monomer measured using a DSC Discovery (manufactured by TA Instruments). Specifically, the homopolymer of a target monomer is heated to 180°C at a rate of 20°C / min, slowly cooled to -100°C, and then heated to 100°C at a rate of 10°C / min, and data on the endothermic transition curve are obtained. Based on the obtained data, the inflection point of the endothermic transition curve can be determined as the glass transition temperature.

[0023] In this specification, "light transmittance" means total light transmittance.

[0024] In this specification, "b * The "color value" is the hue as measured by the CIE (International Commission on Illumination).

[0025] In this specification, the term "light-emitting element" includes an organic light-emitting element or an inorganic light-emitting element, and may refer to an element containing a light-emitting material such as an LED (light emitting diode), an OLED (organic light emitting diode), a QLED (quantum dot light emitting diode), or a phosphor.

[0026] In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0027] In this specification, when a numerical range is stated, "X to Y" means "at least X and at most Y."

[0028] According to one embodiment, the optical member of the present invention may be applied to an optical display device, such as a light emitting device display device, that does not require a polarizing plate including a polarizer. By replacing the polarizing plate, the optical member can eliminate the phenomenon of light emitting devices being damaged by external light, thereby shortening the lifespan of the light emitting device display device.

[0029] According to one embodiment, the optical element exhibits a small change in light transmittance at a wavelength of 380 nm even when exposed to UV light for a long period of time under repeated temperature changes between room temperature and high temperature, which means that damage to the light emitting element due to external light can be prevented even when exposed to UV light for a long period of time under repeated temperature changes between room temperature and high temperature.

[0030] In this regard, the optical member has a light transmittance change ΔT of 0% as expressed in the following equation 1. Even if the optical member is exposed to ultraviolet rays for a long time under repeated temperature changes between room temperature and high temperature, the light emitting element is less damaged, and the life of the light emitting element display device can be improved.

[0031] [Formula 1] △T=|T2-T1|

[0032] In Equation 1, T1 is the light transmittance (unit: %) of the optical component at a wavelength of 380 nm, T2 is measured by holding the optical component at 25°C for 4 hours, then at 63°C for 8 hours, while exposing the optical component to light at a wavelength of 340 nm and an intensity of 0.35 W / m 2 This is the light transmittance (unit: %) of the optical member at a wavelength of 380 nm after a total of 21 cycles of light irradiation, which is defined as one cycle.

[0033] In one embodiment, in Equation 1, T1 may be 0.05% or less, for example, 0.04% or less, for example, 0% to 0.04%.

[0034] In one embodiment, in Equation 1, T2 may be 0.05% or less, for example, 0.04% or less, for example, 0% to 0.04%.

[0035] According to one embodiment, the optical element maintains a hue of b even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature. * This provides an optical element with a small change in hue b value, even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature. *Since the value does not increase, problems such as changes or deterioration of screen quality even after long-term use can be eliminated.

[0036] In this regard, the optical member has a color b of the following Equation 2: * Amount of change in value △b * The value of b of the hue may be less than 0.4. This can solve the problem that the quality of the display of the light-emitting element changes or deteriorates even when exposed to ultraviolet rays for a long period of time under repeated temperature changes between room temperature and high temperature. * Amount of change in value △b * may be equal to or greater than 0 and less than 0.4.

[0037] [Formula 2] △b * =|(b * 2)-(b * 1)|

[0038] In Equation 2, (b * 1) is the hue of the optical component b * is the value, (b * 2) The optical component was kept at 25°C for 4 hours, and then at 63°C for 8 hours, during which time the optical component was exposed to light with a wavelength of 340 nm and an intensity of 0.35 W / m 2 The color of the optical component after 21 cycles of light irradiation is b * value.

[0039] In one embodiment, in Equation 2, (b * 1) may be 7 or less, for example 6.8, for example 0 to 6.8, or 4 to 6.8.

[0040] In one embodiment, in Equation 2, (b * 2) may be 7 or less, for example 6.8, for example 0 to 6.8, or 4 to 6.8.

[0041] According to one embodiment, the optical member has a high peel strength from an optical display panel and is excellent in durability.

[0042] An optical member according to an embodiment will be described below.

[0043] The optical member includes an adhesive layer and a substrate film laminated on one surface of the adhesive layer, and the adhesive layer includes a cured product of a composition including a UV absorber and a (meth)acrylic copolymer. The optical member has a change in light transmittance ΔT of 0% in Equation 1 and a change in hue b of Equation 2. * Amount of change in value △b * is less than 0.4.

[0044] A release film may be further laminated on the other side of the adhesive layer to protect the adhesive layer.

[0045] The configuration of the optical member will be described in detail below.

[0046] <Adhesive layer> The adhesive layer can adhere the optical member to the panel for an optical display device. The adhesive layer contains a cured product of the composition described below, and therefore, even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature, the change in light transmittance at a wavelength of 380 nm is small, and the change in hue is small. * It is possible to provide an optical member having a small change in value, a high peel strength from an optical display panel, and excellent durability.

[0047] In one embodiment, the cured product may be a thermoset of the composition.

[0048] The composition includes a UV absorber and a (meth)acrylic copolymer.

[0049] The UV absorber can function to absorb light in the wavelength range of 360 nm to 410 nm. Absorption of light in the wavelength range of 360 nm to 410 nm can significantly prevent damage to the light emitting element caused by external light.

[0050] In one embodiment, the UV absorber may be an indole-based UV absorber.

[0051] Indole-based UV absorbers have lower light transmittance not only in the wavelength region of 360 nm to 410 nm but also at wavelengths of 400 nm and 405 nm compared to other UV absorbers, and therefore can sufficiently suppress damage to light-emitting elements. In one embodiment, an optical component containing an indole-based UV absorber may have a light transmittance of 5% or less, for example, 0% to 5%, at a wavelength of 405 nm.

[0052] Furthermore, the indole UV absorber can provide an appropriate range of light transmittance at a wavelength of 420 nm, thereby achieving the effect of providing high light efficiency. In one embodiment, the optical member containing the indole UV absorber may have a light transmittance at a wavelength of 420 nm of 25% or more, for example, 25% to 50%.

[0053] Furthermore, the indole UV absorber can provide high light efficiency by providing a light transmittance in an appropriate range at a wavelength of 450 nm. In one embodiment, the optical member containing the indole UV absorber may have a light transmittance of 87% or more, for example, 87% to 90%, at a wavelength of 450 nm.

[0054] In one embodiment, the indole-based UV absorber can include one or more of the compounds represented by the following general formula 1 and the following general formula 2.

[0055] [General formula 1] [ka]

[0056] In general formula 1, R 1 is hydrogen or a substituted or unsubstituted C1-C10 alkyl group, R 2 is hydrogen or a substituted or unsubstituted C6-C20 aryl group, R 3 is hydrogen or a substituted or unsubstituted C1-C10 alkyl group, R4 is hydrogen, a cyano group (CN), or a substituted or unsubstituted C1-C10 alkyl group; R 5 is a cyano group or -(C=O)OR 6 and R 6 is a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C6 to C20 aryl group.

[0057] [General formula 2] [ka]

[0058] In general formula 2, R 1 is hydrogen or a substituted or unsubstituted C1-C10 alkyl group, R 2 is hydrogen or a substituted or unsubstituted C6-C20 aryl group, R 3 is hydrogen or a substituted or unsubstituted C1 to C10 alkyl group.

[0059] R 1 Specifically, R is a C1 to C5 alkyl group, more specifically a methyl group. 2 Specifically, R is a C6 to C10 aryl group, more specifically a phenyl group. 3 Specifically, R is hydrogen or a C1 to C5 alkyl group, more specifically hydrogen. 4 Specifically, R is a cyano group. 5 is specifically a cyano group or -(C=O)-OR 6 R 6 is a substituted or unsubstituted C1 to C5 alkyl group. More specifically, the compound represented by general formula 1 can include a compound represented by the following general formula 1-1 or 1-2.

[0060] [General formula 1-1] [ka]

[0061] [General formula 1-2] [ka]

[0062] The compound represented by general formula 1 has a melting point of 100°C or higher, specifically 140°C to 220°C, and may be in a solid phase at room temperature. The compound represented by general formula 1 may be synthesized by a conventional synthesis method known to those skilled in the art, and commercially available products may be used.

[0063] The compound represented by General Formula 1 has an absorbance (1 cm path length) of 0.8 AU or more, specifically 0.8 AU to 1.0 AU, at a wavelength of 390 nm at a concentration of 10 mg / L in chloroform. The maximum absorption wavelength may be greater than 390 nm, specifically greater than 390 nm but less than 400 nm, more specifically greater than 390 nm but less than 400 nm. Within the above range, light in the ambient wavelength range of 420 nm or less, or 400 nm to 420 nm, can be sufficiently absorbed to reduce transmittance and enhance the ambient light stability of the light-emitting device. The "maximum absorption wavelength" refers to the wavelength showing the maximum absorption peak, i.e., the wavelength showing maximum absorbance in the wavelength-dependent absorbance curve. The "absorbance" can be measured using conventional methods known to those skilled in the art.

[0064] The UV absorber may be contained in the adhesive layer in an amount of 1.25% by weight to 1.8% by weight. This range can sufficiently prevent damage to the light emitting element and eliminate the problem of reduced light transmittance of optical components due to excessive inclusion. For example, the UV absorber may be contained in the adhesive layer in an amount of 1.35% by weight to 1.65% by weight.

[0065] The UV absorber may be contained in an amount of 1.0 to 5 parts by weight, for example, 1.2 to 2.5 parts by weight, relative to 100 parts by weight of the (meth)acrylic copolymer. Within this range, low light transmittance at a wavelength of 380 nm is easily achieved, and excessive inclusion of the UV absorber may result in a change in hue. *This can prevent the value from becoming too high.

[0066] The optical element containing a UV absorber can provide the above-mentioned effects to some extent. However, when an optical element containing only such a UV absorber is exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature, the amount of change in light transmittance at a wavelength of 380 nm is large and the color b * It has been confirmed that the change in value is so large that it is not possible to provide long-term reliability for the light-emitting element.

[0067] On the other hand, as will be described in detail later, when an optical element containing a (meth)acrylic copolymer and a UV absorber, preferably an indole-based UV absorber, is exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature, the amount of change in light transmittance at a wavelength of 380 nm is small, and the change in hue is small. * It was also confirmed that the amount of change in the value could be reduced.

[0068] In one embodiment, the adhesive layer may be a pressure sensitive adhesive.

[0069] The (meth)acrylic copolymer may be a non-carboxylic acid copolymer having no carboxylic acid groups. A (meth)acrylic copolymer having carboxylic acid groups may have reduced durability when adhered to a panel for an optical display device.

[0070] The (meth)acrylic copolymer may be a copolymer of a monomer mixture containing a (meth)acrylic monomer having an alkyl group whose homopolymer has a glass transition temperature of −40° C. or lower, a monomer whose homopolymer has a glass transition temperature of 15° C. or higher, and a (meth)acrylic monomer having a hydroxyl group.

[0071] In one embodiment, the total content of the (meth)acrylic monomer having an alkyl group whose homopolymer has a glass transition temperature of -40°C or lower, the monomer whose homopolymer has a glass transition temperature of 15°C or higher, and the (meth)acrylic monomer having a hydroxyl group may be 99 mol% or higher, for example, 99 mol% to 100 mol%, or 100 mol%, in the monomer mixture. Within this range, the effects of the optical member described above can be easily achieved.

[0072] A (meth)acrylic monomer having an alkyl group whose homopolymer has a glass transition temperature of -40°C or less increases the peel strength of the adhesive layer and facilitates the formation of a matrix for the adhesive layer. For example, the (meth)acrylic monomer having an alkyl group may have a homopolymer having a glass transition temperature of -80°C to -40°C.

[0073] Preferably, the (meth)acrylic monomer having an alkyl group may have a homopolymer having a glass transition temperature of −80° C. to −50° C., for example, −80° C. to −60° C. If the temperature is within the above range, the above-mentioned effects of the optical member can be easily achieved when a homopolymer having a high glass transition temperature, which will be described later, is combined with the (meth)acrylic monomer.

[0074] The (meth)acrylic monomer may contain a (meth)acrylic acid ester having a linear or branched alkyl group having 1 to 8 carbon atoms at the ester moiety. Here, the "number of carbon atoms" refers only to the number of carbon atoms constituting the main chain of the alkyl group. Preferably, the number of carbon atoms may be 6 to 8.

[0075] For example, the (meth)acrylic monomer may include, but is not limited to, one or more of n-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, or iso-octyl (meth)acrylate. These may be included alone or in combination. Preferably, the (meth)acrylic monomer may be 2-ethylhexyl (meth)acrylate.

[0076] The (meth)acrylic monomer may be contained in the monomer mixture in an amount of 65 mol % to 90 mol %, for example, 70 mol % to 90 mol %, or 70 mol % to 85 mol %. Within this range, the peel strength of the adhesive layer is likely to be increased.

[0077] Monomers with a homopolymer glass transition temperature of 15°C or higher may be essential for achieving the effects of the optical member described above. Monomers with a homopolymer glass transition temperature of less than 15°C cause deterioration of optical properties during a solar test, and when the optical member is exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature, the change in light transmittance at a wavelength of 380 nm is large and the color b * The amount of change in the value may also become large, which may be a problem.

[0078] Preferably, the monomer having a homopolymer glass transition temperature of 15° C. or higher may have a homopolymer glass transition temperature of 15° C. to 260° C., for example, 19° C. to 250° C. When in the above range, the effects of the optical member described above can be easily achieved in combination with the above-mentioned (meth)acrylic monomer having a homopolymer glass transition temperature of low.

[0079] The monomer having a glass transition temperature of 15°C or higher when forming a homopolymer may include one or more of a (meth)acrylic acid ester having an alkyl group or an alicyclic group at the ester moiety, and a maleimide having an alicyclic group or an aromatic group.

[0080] Preferably, the alkyl group-containing ester monomer having a homopolymer glass transition temperature of 15°C or higher may be tert-butyl (meth)acrylate or vinyl acetate. Preferably, the alicyclic group-containing ester monomer having a homopolymer glass transition temperature of 15°C or higher may include one or more of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, and dicyclopentadienyl (meth)acrylate. Preferably, the alicyclic group-containing maleimide monomer having a homopolymer glass transition temperature of 15°C or higher may be N-cyclohexylmaleimide or the like. Preferably, the aromatic group-containing maleimide monomer having a homopolymer glass transition temperature of 15°C or higher may be phenylmaleimide or 2-methyl-N-phenylmaleimide.

[0081] The monomer having a homopolymer glass transition temperature of 15°C or higher may be contained in the monomer mixture at 5 mol% to 40 mol%, for example, 10 mol% to 30 mol%, 10 mol% to 27 mol%, or 15 mol% to 30 mol%. Within the above range, the optical component can easily satisfy the ranges of Formula 1 and Formula 2 without affecting the high peel strength of the adhesive layer.

[0082] The (meth)acrylic monomer having a hydroxyl group can increase the peel strength of the adhesive layer by reacting with a curing agent. The (meth)acrylic monomer having a hydroxyl group can include a (meth)acrylic acid ester having an alkyl group having 1 to 20 carbon atoms and having one or more hydroxyl groups at the ester moiety. For example, it can include one or more of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 1-chloro-2-hydroxypropyl (meth)acrylate. These may be used alone or in combination of two or more.

[0083] The (meth)acrylic monomer having a hydroxyl group may be contained in the monomer mixture in an amount of 0.1 mol % to 5 mol %, for example, 0.5 mol % to 3 mol %, or 0.5 mol % to 2 mol %. Within this range, the mechanical strength of the adhesive layer can be maintained and the formula 1 and formula 2 can be satisfied.

[0084] The monomer mixture may not contain a (meth)acrylic acid ester having a long-chain alkyl group. If a (meth)acrylic acid ester having a long-chain alkyl group is contained, problems may arise in that the cohesive strength and adhesive properties of the adhesive layer are not suitable. "A (meth)acrylic acid ester having a long-chain alkyl group" may mean a (meth)acrylic acid ester having an alkyl group having 10 to 25 carbon atoms. Here, the "number of carbon atoms" refers only to the number of carbon atoms constituting the main chain of the long-chain alkyl group.

[0085] The (meth)acrylic copolymer may have a glass transition temperature of −60° C. to −10° C., for example, −60° C. to −30° C., −60° C. to −40° C., or −60° C. to −50° C. If the temperature is within the above range, the effects of the optical member described above can be easily achieved.

[0086] The (meth)acrylic copolymer may have a weight-average molecular weight of 500,000 g / mol to 1,500,000 g / mol, for example, 500,000 g / mol to 1,000,000 g / mol, or 600,000 g / mol to 1,000,000 g / mol. Within this range, the effects of the optical member described above can be easily achieved.

[0087] The (meth)acrylic copolymer can be produced by polymerizing a monomer mixture using a conventional polymerization method. The polymerization method can include conventional methods known to those skilled in the art. For example, the (meth)acrylic copolymer can be produced by adding an initiator to the monomer mixture and then performing conventional copolymer polymerization, such as suspension polymerization, emulsion polymerization, or solution polymerization. The polymerization temperature can be 65°C to 70°C, and the polymerization time can be 6 to 8 hours. The initiator can be a conventional initiator containing an azo polymerization initiator and / or a peroxide such as benzoyl peroxide or acetyl peroxide.

[0088] The composition may further comprise a curing agent.

[0089] The curing agent can react with the (meth)acrylic copolymer to provide release force.

[0090] The curing agent may include a heat curing agent, which can easily form an adhesive layer from the adhesive layer composition containing the UV absorber.

[0091] The curing agent may be contained in an amount of 0.1 to 5 parts by weight, for example, 0.05 to 2.5 parts by weight, relative to 100 parts by weight of the (meth)acrylic copolymer. Within this range, the adhesive layer composition is crosslinked to provide adhesive strength, and a decrease in transparency due to use of an excessive amount can be prevented.

[0092] The thermal curing agent may include one or more of an isocyanate-based curing agent, a metal chelate-based curing agent, an epoxy-based curing agent, an aziridine-based curing agent, an amine-based curing agent, and a thermal polymerization initiator. For example, one or more of an isocyanate-based curing agent and a metal chelate-based curing agent may be included. These may be included alone or in combination of two or more.

[0093] The isocyanate curing agent is not particularly limited to a difunctional or higher, for example, a difunctional to hexafunctional isocyanate curing agent, but may include one or more of xylene diisocyanate (XDI) including m-xylene diisocyanate, methylene bis(phenyl isocyanate) (MDI) including 4,4'-methylene bis(phenyl isocyanate), naphthalene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or an adduct thereof.

[0094] The metal chelate curing agent may include a coordination compound of a polyvalent metal such as aluminum, etc. For example, the metal chelate curing agent may include an aluminum chelate compound such as trisethylacetoacetate aluminum, ethylacetoacetate aluminum diisopropylate, or trisacetylacetonate aluminum.

[0095] The adhesive layer composition may contain a solvent. The solvent improves the coating properties of the adhesive layer composition and can prevent the adhesive layer composition from curing itself. Conventional solvents known to those skilled in the art may be used as the solvent. For example, the solvent may include one or more of methyl ethyl ketone, ethyl acetate, and toluene.

[0096] The adhesive layer composition may further include one or more of a silane coupling agent, a reworking agent, a curing catalyst, an antistatic agent, and a curing catalyst.

[0097] Silane coupling agents can produce adhesive layers with high adhesive strength to substrates such as glass. Silane coupling agents can include conventional silane coupling agents known to those skilled in the art. For example, the silane coupling agent can include, but is not limited to, one or more selected from the group consisting of silicon compounds having an epoxy structure, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; silicon compounds containing polymerizable unsaturated groups, such as vinyltrimethoxysilane, vinyltriethoxysilane, and (meth)acryloxypropyltrimethoxysilane; silicon compounds containing amino groups, such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; and 3-chloropropyltrimethoxysilane. The silane coupling agent may be contained in an amount of 0.001 to 5 parts by weight, specifically 0.001 to 3 parts by weight, relative to 100 parts by weight of the (meth)acrylic copolymer. Within this range, excellent durability and reliability can be achieved, and changes in components and physical properties over time can be reduced.

[0098] The rework agent enhances the reworkability of the adhesive layer and may comprise a polysiloxane oligomer or a mixture containing the same. The rework agent may be contained in an amount of 0.001 to 5 parts by weight, specifically 0.005 to 1 part by weight, per 100 parts by weight of the (meth)acrylic copolymer. Within this range, the reworkability can be enhanced without affecting the physical properties of the adhesive layer.

[0099] The antistatic agent suppresses the generation of static electricity during rework of the adhesive layer and may contain a conventional antistatic agent. The antistatic agent may be contained in an amount of 0.001 to 5 parts by weight, specifically 0.1 to 5 parts by weight, per 100 parts by weight of the (meth)acrylic copolymer. Within this range, antistatic properties can be provided without affecting the physical properties of the adhesive layer.

[0100] The curing catalyst may be a boron-based compound (for example, a boron trifluoride (boron trifluoride) complex, specifically, an ether complex of boron trifluoride, a tetrahydrofuran complex of boron trifluoride (BF3-THF), an aniline complex of boron trifluoride (BF3-Aniline), more specifically, BF3·O(CH3)2 (boron trifluoride dimethyl ether complex), BF3·O(C2H5)2 (boron trifluoride diethyl ether complex)), a phosphine-based compound (for example, triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, triphenylphosphine, The curing catalyst may include one or more of the following: secondary amine or tertiary amine compounds (e.g., alpha-tertiary amine compounds such as triethylamine, benzyldiethylamine, or benzyldimethylamine (e.g., KH-30, Kukdo)), imidazole compounds (e.g., 2-methylimidazole, 2-phenylimidazole, or 2-phenyl-4-methylimidazole), and sulfonic acid compounds (e.g., paratoluenesulfonic acid, benzenedodecylsulfonic acid, naphthalenesulfonic acid, naphthalenedisulfonic acid, methanesulfonic acid, methanedisulfonic acid, phenolsulfonic acid, etc.). The curing catalyst may be included in an amount of 0.01 to 5 parts by weight, specifically 0.05 to 2 parts by weight, per 100 parts by weight of the (meth)acrylic copolymer. The amount in the above range is effective in shortening the curing rate.

[0101] The adhesive layer composition may further contain common additives. The additives may include antioxidants, tackifying resins, plasticizers, etc. The additives may be contained in an amount of 0.001 to 5 parts by weight, specifically 0.01 to 1 part by weight, per 100 parts by weight of the (meth)acrylic copolymer. Within the above range, the effects of the additives can be obtained without affecting the physical properties of the adhesive layer.

[0102] The composition for the adhesive layer may have a viscosity of 1,000 cPs to 4,000 cPs at 25° C. Within this range, it becomes easy to adjust the thickness of the adhesive layer, and the adhesive layer can have no unevenness and the coating surface can be made uniform.

[0103] The adhesive layer may have a thickness of 100 μm or less, specifically 5 μm to 50 μm.Within this range, the adhesive layer can be used in optical display devices.

[0104] The adhesive layer may have a peel strength from a glass plate of 300 gf / inch or more, for example, 300 gf / inch to 800 gf / inch, or 300 gf / inch to 600 gf / inch. When the peel strength is within the above range, high reliability can be maintained with respect to the substrate film.

[0105] The adhesive layer can be produced by coating the adhesive layer composition to a predetermined thickness, drying it, and then aging it at a constant temperature and humidity of 25°C to 35°C and a relative humidity of 30% to 60%, but is not limited to this.

[0106] <Base film> The substrate film is formed on the adhesive layer to protect the adhesive layer and increase the mechanical strength of the optical component. In one embodiment, the substrate film may be formed directly on the adhesive layer. Here, "directly formed" means that there is no other adhesive or bonding layer between the substrate film and the adhesive layer.

[0107] In one embodiment, the substrate film may have a light transmittance of 80% or more, for example, 88% to 99%, at a wavelength of 270 nm to 800 nm. When the transmittance is in this range, the light path of external light and internal light is not affected, thereby increasing light efficiency.

[0108] In one embodiment, the substrate film may have a light transmittance of 1% or less at a wavelength of 380 nm, for example, 0.01% to 0.05%.

[0109] In one embodiment, the base film has a color of b * The value of b of the hue of the optical member may be 4.0 to 8.0, for example, 4.5 to 7.0. * It can be made to have no effect on the value.

[0110] The substrate film may include one or more optically clear protective films or coating layers.

[0111] When the substrate film is a protective film type, it may include a protective film formed of an optically transparent resin. The protective film may be formed by melting and extruding the resin. If necessary, a stretching process may be added. The resin may include one or more of cellulose ester-based resins including triacetyl cellulose, cyclic polyolefin-based resins including acyclic olefin polymers (COP), polycarbonate-based resins, polyester-based resins including polyethylene terephthalate (PET), polyethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic polyolefin-based resins, polyacrylate-based resins including polymethyl methacrylate resin, polyvinyl alcohol-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins.

[0112] When the substrate film has a protective coating layer, it can have good adhesion to the adhesive layer, transparency, mechanical strength, thermal stability, moisture blocking properties, and durability. In one embodiment, the protective coating layer for the substrate film can be formed from a radiation-curable resin composition containing a radiation-curable compound and a polymerization initiator.

[0113] The radiation-curable compound may include one or more of a cationically polymerizable curable compound, a radically polymerizable curable compound, a urethane resin, and a silicone resin. The cationically polymerizable curable compound may be an epoxy-based compound having at least one epoxy group in the molecule, or an oxetane-based compound having at least one oxetane ring in the molecule. The radically polymerizable curable compound may be a (meth)acrylic-based compound having at least one (meth)acryloyloxy group in the molecule.

[0114] The thickness of the substrate film may be 5 μm to 200 μm, specifically 30 μm to 120 μm, or 50 μm to 100 μm in the case of a protective film type, or 5 μm to 50 μm in the case of a protective coating layer type. If the thickness is within the above range, the substrate film can be used in optical display devices.

[0115] A functional coating layer, such as a hard coating layer, an anti-fingerprint layer, or an anti-reflection layer, may be further formed on another surface of the substrate film.

[0116] According to one embodiment, an optical display device is provided.

[0117] An optical display device includes the optical member.

[0118] In one embodiment, the optical display device can include an optical display panel and an optical member laminated on the panel.

[0119] In one embodiment, the optical display device does not include a polarizer. Even if the optical display device does not include a polarizer, the optical member can replace the function of the polarizer, thereby preventing damage to the light-emitting element.

[0120] The optical display device may include, but is not limited to, a light emitting device display device such as a liquid crystal display device or an organic light emitting display device. [Example]

[0121] The present invention will be described in more detail with reference to preferred embodiments thereof below, which are merely examples of the present invention and should not be construed as limiting the scope of the present invention in any way.

[0122] <Production Example 1: Production of (meth)acrylic copolymer> Ethyl acetate and / or methyl ethyl ketone or toluene was added to a 1 L reactor configured for reflux under nitrogen gas and equipped with a cooling device for easy temperature control. 100 parts by weight of a monomer mixture containing 79 mol% 2-ethylhexyl acrylate (2-EHA), 20 mol% isobornyl acrylate (IBXA), and 1 mol% 4-hydroxybutyl acrylate (4-HBA) was added to the reactor. Nitrogen gas was introduced into the reactor for 30 minutes to displace the oxygen in the reactor and remove oxygen from the monomer mixture, after which the internal temperature of the reactor was maintained at 60°C. After stirring the monomer mixture uniformly, 0.06 parts by weight of V601 (dimethyl 2,2'-azobis(2-methylpropionate)) was added as an initiator and reacted for 4 hours. The internal temperature of the reactor was raised to 65°C, and the initiator was further added. After reacting for an additional 2 hours at 65°C, the mixture was cooled to room temperature and methyl ethyl ketone was added to prepare a 25% by weight (meth)acrylic copolymer solution. The weight average molecular weight and glass transition temperature of the prepared (meth)acrylic copolymer were determined by GPC and DSC analysis.

[0123] <Production Examples 2 to 10: Production of (meth)acrylic copolymers> (Meth)acrylic copolymers were prepared in the same manner as in Preparation Example 1, except that the type and content of the monomers in the monomer mixture were changed as shown in Table 1 below, and the content of the initiator or the reaction time was changed. In Table 1 below, "-" means that the content of the component is 0 mol%.

[0124] [Table 1]

[0125] The abbreviations and terms for the monomers in Table 1 are as follows: 2-EHA: 2-ethylhexyl acrylate (Tg of homopolymer: -65°C) MA: methyl acrylate (Tg of homopolymer: 8°C) IBXA: Isobornyl acrylate (Tg of homopolymer: 94°C) tert-BA: tert-butyl acrylate (Tg of homopolymer: 41°C) CHA: cyclohexyl acrylate (Tg of homopolymer: 19°C) DCPA: dicyclopentadienyl acrylate (Tg of homopolymer: 120°C) PMI: Phenylmaleimide (Tg of homopolymer: 250°C) N-CMI: N-cyclohexylmaleimide (Tg of homopolymer: 210°C) BzA: Benzyl acrylate (Tg of homopolymer: 8°C) LA: Lauryl acrylate (Tg of homopolymer: -30°C) 4-HBA: 4-hydroxybutyl acrylate (Tg of homopolymer: -30°C) Mw: Weight average molecular weight of acrylic copolymer (unit: g / mol) Tg: Glass transition temperature of acrylic copolymer (unit: °C)

[0126] The components used in the examples and comparative examples are as follows: (A) (Meth)acrylic copolymer (Meth)acrylic copolymers of the production examples in Table 1 and other (meth)acrylic copolymers (B) Hardener Trimethylolpropane xylene diisocyanate adduct (isocyanate-based curing agent, TD-75, Soken) (C) Curing catalyst DBTDL catalyst (D) NUV-absorbing compounds 2-phenyl-N-methylindole (BONASORB® UA-3912, Orient Chemical Industry Co., Ltd.)

[0127] Example 1 0.09 parts by weight of (B) isocyanate curing agent, 0.0035 parts by weight of (C) curing catalyst, and 1.45 parts by weight of (D) NUV-absorbing compound were mixed with 100 parts by weight of the (meth)acrylic copolymer of Preparation Example 1 on a solids basis, and methyl ethyl ketone was mixed as a solvent in an amount four times the weight of the (meth)acrylic copolymer of Preparation Example 1. The prepared composition was then mixed in a mechanical reactor and stirred at room temperature for 20 minutes, followed by a nitrogen gas flow for 30 minutes to produce a composition for adhesive layer.

[0128] The adhesive layer composition was applied to one side of a release film (silicon-treated, thickness: 38 μm) in a predetermined thickness and dried at 100°C for 4 minutes to form a coating film (thickness: 23 μm). Then, a triacetyl cellulose film (light transmittance at wavelengths of 270 nm to 800 nm: 96.87%, b * The sheet was then covered with a release film (thickness: 38 μm), an adhesive layer (thickness: 23 μm), and a TAC film (thickness: 40 μm) laminated in that order by aging at 35°C and 45% RH (relative humidity) for 2 days.

[0129] <Examples 2 to 6> In Example 1, an adhesive layer-containing sheet in which a release film, an adhesive layer, and a TAC film were laminated in order was produced in the same manner, except that the type of (meth)acrylic copolymer was changed as shown in Table 2 below.

[0130] <Comparative Example 1> The same release film (silicon-treated, thickness: 38 μm) as in Example 1 and triacetyl cellulose film (light transmittance at wavelengths of 270 nm to 800 nm: 96.87%, b *A 15 μm thick cured adhesive layer containing a (meth)acrylic copolymer and a curing agent was used as the adhesive layer. An 8 μm thick layer containing an acrylic resin and 2-phenyl-N-methylindole was used as the hard coating layer. A sheet was produced in which the adhesive layer, triacetyl cellulose film, and hard coating layer were laminated in this order on a release film.

[0131] <Comparative Examples 2 to 8> In Example 1, an adhesive layer-containing sheet in which a release film, an adhesive layer, and a TAC film were laminated in order was produced in the same manner, except that the type of (meth)acrylic copolymer was changed as shown in Table 3 below.

[0132] The adhesive layer-containing sheets produced in the examples and comparative examples were evaluated for the physical properties shown in Table 2 below, and the results are shown in Tables 2 and 3 below.

[0133] The evaluations shown in Tables 2 and 3 below are as follows.

[0134] (1) Peeling force against non-alkali glass plate (unit: gf / inch) The prepared adhesive layer-containing sheet was cut into a 25mm x 200mm piece, and after removing the release film, it was attached to an alkali-free glass plate via the adhesive layer. It was then left at room temperature for 30 minutes to prepare a test piece for measuring peel strength. Using a peel strength tester (manufactured by TA Instruments), the peel strength was measured when peeling the entire adhesive layer and TAC film from the alkali-free glass plate at a peel speed of 300mm / sec, a peel angle of 180°, and a peel temperature of 25°C. The measurement was performed three times, and the average value was calculated.

[0135] (2) Solar test The prepared adhesive layer-containing sheet was cut into a size of 25 mm wide x 200 mm long, and after removing the release film, it was attached to a glass plate to prepare a test specimen. The prepared test specimen was measured for UV spectrum (light transmittance T1 and (b * 1) value) was measured.

[0136] The specimen was then placed in a UV chamber and subjected to a solar test in which it was continuously irradiated with UV light of 340 nm wavelength under specified conditions. Specifically, the solar test conditions were to hold the specimen at 25°C for 4 hours, then at 63°C for 8 hours, while the specimen was irradiated with UV light of 340 nm wavelength and 0.35 W / m 2 A total of 21 cycles were performed, with one cycle consisting of 100 cycles of light irradiation.

[0137] The specimen was then removed from the UV chamber and kept at room temperature for 30 minutes. The UV spectrum (light transmittance T2 and (b * 2) The difference in light transmittance △T and △b before and after the solar test was measured. * The difference in values ​​was calculated.

[0138] (3)Durability The produced adhesive layer-containing sheet was cut into a 156mm wide x 128mm long piece, and after removing the release film, it was laminated to an alkali-free glass plate to produce a test specimen. The produced test specimens were subjected to four conditions: 500 hours at 85°C, 500 hours at 85°C and 85% RH, 500 hours at 60°C and 95% RH, or 500 hours at -40°C followed by 5 hours at 85°C, repeated 50 times. After that, if there were no changes such as bubbles, lifting, cracks, or coloration at the interface between the adhesive layer and the glass plate or the interface between the adhesive layer and the TAC film, it was evaluated as 'Good', and if there were any changes, it was evaluated as 'Poor'.

[0139] [Table 2]

[0140] [Table 3]

[0141] The abbreviations for the materials in Table 3 are as follows: CI-205: Acrylic binder with carboxylic acid groups (Soken) PL-8540: Acrylic binder with carboxylic acid groups (Saiden) CI-247: Acrylic binder without carboxylic acid groups (Soken)

[0142] As shown in Table 2, the optical elements of the examples according to the present invention showed a small change in light transmittance at a wavelength of 380 nm even when exposed to ultraviolet light for a long period of time under repeated temperature changes between room temperature and high temperature. * The optical members according to the examples of the present invention had a high peel strength from the panel for an optical display device and were excellent in durability.

[0143] On the other hand, as shown in Table 3, the optical members of the comparative examples were unable to provide the above-mentioned effects of the present invention.

[0144] Simple modifications or alterations of the present invention can be easily implemented by a person having ordinary skill in the art, and all such modifications and alterations can be considered to be included within the scope of the present invention.

Claims

1. An optical member comprising an adhesive layer and a substrate film laminated on one surface of the adhesive layer, the adhesive layer comprises a cured product of a composition comprising a UV absorber and a (meth)acrylic copolymer, The optical member has a change in light transmittance ΔT of 0% in the following equation (1) and a change in hue b of 0% in the following equation (2). ＊ Amount of change in value △b ＊ An optical element, wherein the value is less than 0.

4. [Formula 1] △T=|T ２ -T １ | (In the above formula 1, T １ is the light transmittance (unit: %) of the optical member at a wavelength of 380 nm, T ２ The optical element was kept at 25°C for 4 hours, and then at 63°C for 8 hours, during which the optical element was irradiated with light having a wavelength of 340 nm and an intensity of 0.35 W / m ２ This is the light transmittance (unit: %) of the optical element at a wavelength of 380 nm after a total of 21 cycles of light irradiation, with one cycle being one cycle of light irradiation. [Formula 2] △b ＊ =|(b ＊ ２ )-(b ＊ １ )| (In the above formula 2, (b ＊ １ ) is the color b of the optical member. ＊ is the value, (b ＊ ２ ) is performed by holding the optical element at 25°C for 4 hours and then at 63°C for 8 hours, while applying light of 340 nm wavelength and 0.35 W / m ２ The light irradiation cycle is defined as one cycle, and the hue of the optical member after a total of 21 cycles is b ＊ value.)

2. The optical member according to claim 1 , wherein the UV absorber is an indole-based UV absorber.

3. The optical member according to claim 2 , wherein the indole-based UV absorber comprises at least one compound represented by the following general formula 1 or 2: [General formula 1] 【Chemical 1】 (In the above general formula 1, R １ is hydrogen or a substituted or unsubstituted C1-C10 alkyl group; R ２ is hydrogen or a substituted or unsubstituted C6-C20 aryl group; R ３ is hydrogen or a substituted or unsubstituted C1-C10 alkyl group; R ４ is hydrogen, a cyano group (CN), or a substituted or unsubstituted C1-C10 alkyl group; R ５ represents a cyano group or —(C═O)O—R ６ and R ６ is a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C6 to C20 aryl group. [General formula 2] 【Chemistry 2】 (In the above general formula 2, R １ is hydrogen or a substituted or unsubstituted C1-C10 alkyl group; R ２ is hydrogen or a substituted or unsubstituted C6-C20 aryl group; R ３ is hydrogen or a substituted or unsubstituted C1 to C10 alkyl group.

4. The optical member according to claim 1 , wherein the UV absorber is contained in the adhesive layer in an amount of 1.25% by weight to 1.8% by weight.

5. The optical member according to claim 1 , wherein the (meth)acrylic copolymer is a non-carboxylic acid copolymer having no carboxylic acid group.

6. The optical member according to claim 1, wherein the (meth)acrylic copolymer is a copolymer of a monomer mixture including a (meth)acrylic monomer having an alkyl group whose homopolymer has a glass transition temperature of −40° C. or lower, a monomer whose homopolymer has a glass transition temperature of 15° C. or higher, and a (meth)acrylic monomer having a hydroxyl group.

7. 7. The optical member according to claim 6, wherein the monomer having a glass transition temperature of 15°C or higher of the homopolymer comprises at least one of a (meth)acrylic acid ester having an alkyl group or an alicyclic group at an ester moiety, and a maleimide having an alicyclic group or an aromatic group.

8. 8. The optical member according to claim 7, wherein the monomer having a glass transition temperature of 15°C or higher of the homopolymer includes one or more of tert-butyl(meth)acrylate, isobornyl(meth)acrylate, cyclohexyl(meth)acrylate, dicyclopentadienyl(meth)acrylate, N-cyclohexylmaleimide, and phenylmaleimide.

9. 7. The optical member according to claim 6, wherein the (meth)acrylic monomer having an alkyl group and having a glass transition temperature of −40° C. or lower of the homopolymer comprises a (meth)acrylic acid ester having a linear or branched alkyl group having 1 to 8 carbon atoms at an ester moiety.

10. 7. The optical member according to claim 6, wherein the total of the (meth)acrylic monomer having an alkyl group which forms a homopolymer with a glass transition temperature of −40° C. or lower, the monomer having a homopolymer with a glass transition temperature of 15° C. or higher, and the (meth)acrylic monomer having a hydroxyl group is 99 mol % or higher in the monomer mixture.

11. The monomer mixture is 65 mol % to 90 mol % of a (meth)acrylic monomer having an alkyl group whose glass transition temperature of the homopolymer is −40° C. or lower, 5 mol % to 30 mol % of a monomer having a glass transition temperature of the homopolymer of 15° C. or higher, and 7. The optical member according to claim 6, wherein the (meth)acrylic monomer having a hydroxyl group is contained in an amount of 0.1 mol % to 5 mol %.

12. The optical member according to claim 1 , wherein the composition further comprises a curing agent.

13. The optical member according to claim 1 , wherein the adhesive layer has a peel strength from a glass plate of 300 gf / inch or more.

14. An optical display device comprising the optical member according to claim 1 .

15. The optical display of claim 14 , wherein the optical display does not include a polarizer.

Images